High serum IgG subclass concentrations in children with e-waste Pb and Cd exposure

Area of Science:

• Environmental Health
• Immunology
• Toxicology

Background:

• Epidemiological studies link lead (Pb) and cadmium (Cd) exposure to altered human immunoglobulin G (IgG) levels.
• Pb and Cd exposure can modulate Th1/Th2 cytokines, affecting IgG subclass production.
• The impact of co-exposure to Pb and Cd on IgG subclasses via Th1/Th2 cytokines in children near e-waste sites remains unstudied.

Purpose of the Study:

• To analyze the associations among blood Pb and Cd levels, Th1/Th2 cytokines, and serum IgG subclasses in children living in e-waste-affected areas.
• To investigate the role of Th1/Th2 cytokines as mediators in the relationship between heavy metal exposure and IgG subclass levels.

Main Methods:

• Cross-sectional study involving 181 children (2-7 years old) from Guiyu (e-waste exposed) and Haojiang (reference) in China.
• Measurement of blood Pb and Cd levels, serum cytokines (IFN-γ, IL-13), and serum IgG subclasses (IgG1, IgG2, IgG3, IgG4).
• Statistical analyses including linear regression and mediation models to assess associations and mediating effects.

Main Results:

• Children from the e-waste area showed higher blood Pb and Cd, elevated serum IgG1 and IgG1+IgG2, increased Th1 cytokine (IFN-γ), and decreased Th2 cytokine (IL-13).
• Increased blood Pb levels correlated positively with IFN-γ and negatively with IL-13.
• Serum IL-13 levels were negatively associated with IgG1 and IgG1+IgG2; IL-13 mediated the effects of Pb on these IgG subclasses.
• Increased blood Cd levels were positively associated with serum IgG1.

Conclusions:

• Heavy metal exposure, especially lead, may impair humoral immune function in children by disrupting the Th1/Th2 cytokine balance and affecting IgG subclass production.
• Findings provide evidence for a link between environmental heavy metal exposure and altered immune responses in children residing in e-waste areas.